# Preamble

This is a work in progress, which started at the beginning of August, 2016. Most of the information introduced so far refer to the current packages QCA and QCAGUI, although by the time this book will be finished the intention is to merge both packages (back) into package QCA.

Most of the examples should work with the current stable version 2.4, but there are situations where version upcoming version 2.5 is needed. In particular, chapter 4 makes extensive use of either new functions like plot1(), or changed argument defaults, for example argument type in function calibrate(), which from version 2.5 will be defaulted to fuzzy. Examples still work with version 2.4, but users should add type = "fuzzy" for the fuzzy calibration.

Also, some of the dialogs are changed in version 2.5, again with an example from the “Calibrate” menu. It’s dialog has been extensively improved, with a new and hopefully useful thresholds setter for the fuzzy calibration.

The structure of this book is different from the former user guide published in 2013. It will of course touch on the same topics and present the same package, but instead of organising chapters on the distinction between crisp, multi-value, and fuzzy sets, a better approach is to organise the book on QCA related analyses: necessity, sufficiency, parameters of fit, calibration etc. This structure is a first proposal, and readers are encouraged to make suggestions: as this is a work in progress, anything is subject to change until reaching a proper publication stage.

Many things have changed in the R packages over the past two years, with many new additions: the graphical user interface, or drawing Venn diagrams up to seven sets, just to mention a couple of the most spectacular. However, the QCA functionality relies on the same minimization engine from version 0.6-5, so results are backwards compatible.

Topic related chapters will contain examples for all QCA variants (cs, mv and fs, also extentions) as well as detailed instructions how to perform each of the analyses using both command line and using the new graphical user interface.

There are not enough words to describe the amazing work of Yihui Xie and all the team of engineers from RStusio, who provide this public service and especially for the packages knitr, rmarkdown and bookdown which allow this form of HTML publication (among others).

The author wishes to thank in advance for any feedback, as well as suggestions and likely corrections to the book content, sent to: dusa.adrian@unibuc.ro